The present invention relates to an adhesive system and associated method for attaching lettering or other graphics to a garment or similar substrate, by the application of heat and pressure.
My co-pending U.S. patent application No. 805,000 filed Dec. 10, 1991 for "Heat Applied Athletic Lettering", describes a layered plastic web that is particularly adapted for attachment of urethane lettering or the like to a garment substrate. A web is fabricated by coating at least one layer of thermoplastic material, preferably pigmented polyurethane, onto a transparent or transluscent plastic film, preferably polyester. The resulting web can readily be cut by a computer controlled blade to produce virtually any graphic pattern, including intricate or small letters that may be connected or separated from each other, without penetration of the blade through the carrier sheet. The graphic sheet adheres strongly enough to the carrier sheet, preferably with a peel value in the range of 15-30 ounces, to prevent sliding of the graphic sheet relative to the carrier sheet during cutting, yet permitting release of the carrier sheet after attachment of the graphic by the application of heat and pressure. Thus an "adhesive up" type of web is provided for polyurethane lettering, whereby the graphic can be cut and peeled from the web, and the graphic, while still adhered to the carrier sheet, placed against the fabric. The clarity of the plastic carrier sheet permits exact placement of the letters on the fabric, e.g., on or relative to a shirt pocket.
Despite the significant advance in the art represented by the invention described in said application, neither that invention nor any other lettering system known to the inventor, is capable of easily and reliably attaching lettering or graphics to nylon, satin, canvas, or similar garment substrates that have been treated to resist or repel water, stains, etc. Stahls' Encyclopedia of Heat Applied Lettering, 2nd Ed. Version 2.1 (Library of Congress Registration TXU 133-924) warns on page 12 that Flock lettering will fall off waterproof or even satin jackets, although they appear to stick initially. Promotional materials pertaining to Gerber Heat Transfer Flock, Lextra multicolor velour decoration products, and Hix heat transfer application machines, all carry a warning against attempting to apply plastic lettering material to a nylon or similar substrate.